The commissioner may at any time, after a hearing of which not less than twenty (20) days’ written notice has been given to the insurer, withdraw approval of any form on any of the grounds stated in this chapter. It shall be unlawful for the insurer to issue that form or use it in connection with any policy after the effective date of the withdrawal of approval. The notice of any hearing called under this section shall specify the matter to be considered at the hearing and any decision affirming disapproval or directing withdrawal of approval under this chapter shall be in writing and shall specify the reasons for the decision.